The present invention relates to thermally curable adhesives. In particular, the present invention relates to thermally curable adhesives that are suitable for use as electrically conductive materials in the fabrication of electronic devices, integrated circuits, semiconductor devices, passive components, solar cells, solar modules, and/or light emitting diodes.
Electrically conductive materials are used for a variety of purposes in the fabrication and assembly of electronic devices, integrated circuits, semiconductor devices, passive components, solar cells, solar modules, and/or light emitting diodes.
In general, electrically conductive adhesives (ECAs) provide a mechanical bond between two surfaces and conduct electricity. Typically, ECA formulations are made of a polymer resin filled with electrically conductive metal fillers. The resin generally provides a mechanical bond between two substrates, while the electrically conductive fillers generally provide the desired electrical interconnection.
For instance, WO 2008/048207 A2 discloses electrically conductive adhesive compositions having cured low modulus elastomer and metallurgically-bonded micron-sized metal particles and nanosized metal particles. Said electrically conductive adhesive compositions often exhibit rather high processing viscosities, low storage stabilities and/or an insufficient electrical conductivity.
As electronic devices and the corresponding connecting areas between components and substrates are becoming continuously smaller, there is a need for electrically conductive materials, such as electrically conductive adhesives, that can provide an improved electrical interconnection between small contact areas.
Additionally, it would be desirable to provide ECAs, which exhibit a low processing viscosity, and a low processing temperature. Moreover, a particular challenge with electrically conductive adhesives is implementing the appropriate balance of filler loading, adhesive strength, curing speed, electrical conductivity and stable electrical contact resistance.
Hence, there is a need for new electrically conductive adhesives that provide an improved electrically conductive interconnection between small contact areas, such as metallic electrodes, a low processing viscosity, and a low processing temperature.